Deferred loading messages (#904)

* Refactorings

* Add android app with deferred loading

* Add german again

* all

* Fix analysis

* Fix deferred loading

* sort imports

* Nicer linebreaks

* Add license

* Fixes as per review

* Extact to class

* Rename

* Fix bugs

* Adapt workflow

.github/workflows/messages.yml

@@ -49,6 +49,6 @@ jobs:
       - name: Regenerate and run example
         working-directory: pkgs/messages/example
         run: |
-          dart run messages
-          git diff --exit-code
-          dart run
+          dart run messages || exit 1
+          git diff --exit-code || exit 1
+          dart run || exit 1

pkgs/messages/example/bin/example.dart

@@ -6,7 +6,7 @@
 
 import 'dart:io';
 
-import 'package:example/messages.g.dart';
+import 'package:example/AboutPage_messages.g.dart';
 
 Future<void> main(List<String> arguments) async {
   final messages = AboutPageMessages(

pkgs/messages/example/lib/AboutPage_en_empty.g.dart

@@ -0,0 +1,2 @@
+// This is a helper file for deferred loading of the messages for locale en,
+// generated by `dart run messages`.

pkgs/messages/example/lib/AboutPage_fr_empty.g.dart

@@ -0,0 +1,2 @@
+// This is a helper file for deferred loading of the messages for locale fr,
+// generated by `dart run messages`.

pkgs/messages/example/lib/messages.g.dart → pkgs/messages/example/lib/AboutPage_messages.g.dart

@@ -1,30 +1,13 @@
 // Generated by package:messages_builder.
 
-// ignore_for_file: non_constant_identifier_names
+// ignore_for_file: library_prefixes, non_constant_identifier_names
+// ignore_for_file: unused_import
 
 import 'package:intl/intl.dart';
 import 'package:messages/messages_json.dart';
 
-Message _pluralSelector(
-  num howMany,
-  String locale, {
-  required Message other,
-  Message? few,
-  Message? many,
-  Map<int, Message>? numberCases,
-  Map<int, Message>? wordCases,
-}) {
-  return Intl.pluralLogic(
-    howMany,
-    few: few,
-    many: many,
-    zero: numberCases?[0] ?? wordCases?[0],
-    one: numberCases?[1] ?? wordCases?[1],
-    two: numberCases?[2] ?? wordCases?[2],
-    other: other,
-    locale: locale,
-  );
-}
+import 'AboutPage_en_empty.g.dart' deferred as AboutPage_en_empty;
+import 'AboutPage_fr_empty.g.dart' deferred as AboutPage_fr_empty;
 
 class AboutPageMessages {
   AboutPageMessages(this._assetLoader);
@@ -60,6 +43,12 @@ class AboutPageMessages {
       if (dataFile == null) {
         throw ArgumentError('Locale $locale is not in $knownLocales');
       }
+      if (locale == 'en') {
+        await AboutPage_en_empty.loadLibrary();
+      } else if (locale == 'fr') {
+        await AboutPage_fr_empty.loadLibrary();
+      }
+
       final data = await _assetLoader(dataFile);
       final messageList = MessageListJson.fromString(data, _pluralSelector);
       if (messageList.preamble.hash != info?.$2) {
@@ -98,75 +87,23 @@ class AboutPageMessages {
   String get otherMsg => _currentMessages.generateStringAtIndex(4, []);
 }
 
-class HomePageMessages {
-  HomePageMessages(this._assetLoader);
-
-  final Future<String> Function(String id) _assetLoader;
-
-  String _currentLocale = 'en';
-
-  final Map<String, MessageList> _messages = {};
-
-  static const _dataFiles = {
-    'de': ('packages/example/assets/testarb_de.arb.json', 'hbDN1MhX'),
-    'en': ('packages/example/assets/testarb.arb.json', 'dr9Md951')
-  };
-
-  String get currentLocale => _currentLocale;
-
-  MessageList get _currentMessages => _messages[currentLocale]!;
-
-  String getById(
-    String id, [
-    List<dynamic> args = const [],
-  ]) {
-    return _currentMessages.generateStringAtId(id, args);
-  }
-
-  static Iterable<String> get knownLocales => _dataFiles.keys;
-
-  Future<void> loadLocale(String locale) async {
-    if (!_messages.containsKey(locale)) {
-      final info = _dataFiles[locale];
-      final dataFile = info?.$1;
-      if (dataFile == null) {
-        throw ArgumentError('Locale $locale is not in $knownLocales');
-      }
-      final data = await _assetLoader(dataFile);
-      final messageList = MessageListJson.fromString(data, _pluralSelector);
-      if (messageList.preamble.hash != info?.$2) {
-        throw ArgumentError('''
-              Messages file for locale $locale has different hash "${messageList.preamble.hash}" than generated code "${info?.$2}".''');
-      }
-      _messages[locale] = messageList;
-    }
-    _currentLocale = locale;
-  }
-
-  Future<void> loadAllLocales() async {
-    for (final locale in knownLocales) {
-      await loadLocale(locale);
-    }
-  }
-
-  String helloAndWelcome(
-    String firstName,
-    String lastName,
-  ) =>
-      _currentMessages.generateStringAtIndex(0, [firstName, lastName]);
-
-  String helloAndWelcome2(
-    String firstName,
-    String lastName,
-  ) =>
-      _currentMessages.generateStringAtIndex(1, [firstName, lastName]);
-
-  String newMessages(int newMessages) =>
-      _currentMessages.generateStringAtIndex(2, [newMessages]);
-
-  String newMessages2(
-    String gender,
-    int newVar,
-  ) =>
-      _currentMessages.generateStringAtIndex(3, [gender, newVar]);
+Message _pluralSelector(
+  num howMany,
+  String locale, {
+  required Message other,
+  Message? few,
+  Message? many,
+  Map<int, Message>? numberCases,
+  Map<int, Message>? wordCases,
+}) {
+  return Intl.pluralLogic(
+    howMany,
+    few: few,
+    many: many,
+    zero: numberCases?[0] ?? wordCases?[0],
+    one: numberCases?[1] ?? wordCases?[1],
+    two: numberCases?[2] ?? wordCases?[2],
+    other: other,
+    locale: locale,
+  );
 }

pkgs/messages/example/lib/HomePage_de_empty.g.dart

@@ -0,0 +1,2 @@
+// This is a helper file for deferred loading of the messages for locale de,
+// generated by `dart run messages`.

pkgs/messages/example/lib/HomePage_en_empty.g.dart

@@ -0,0 +1,2 @@
+// This is a helper file for deferred loading of the messages for locale en,
+// generated by `dart run messages`.

pkgs/messages/example/lib/HomePage_messages.g.dart

@@ -0,0 +1,110 @@
+// Generated by package:messages_builder.
+
+// ignore_for_file: library_prefixes, non_constant_identifier_names
+// ignore_for_file: unused_import
+
+import 'package:intl/intl.dart';
+import 'package:messages/messages_json.dart';
+
+import 'HomePage_de_empty.g.dart' deferred as HomePage_de_empty;
+import 'HomePage_en_empty.g.dart' deferred as HomePage_en_empty;
+
+class HomePageMessages {
+  HomePageMessages(this._assetLoader);
+
+  final Future<String> Function(String id) _assetLoader;
+
+  String _currentLocale = 'en';
+
+  final Map<String, MessageList> _messages = {};
+
+  static const _dataFiles = {
+    'de': ('packages/example/assets/testarb_de.arb.json', 'hbDN1MhX'),
+    'en': ('packages/example/assets/testarb.arb.json', 'dr9Md951')
+  };
+
+  String get currentLocale => _currentLocale;
+
+  MessageList get _currentMessages => _messages[currentLocale]!;
+
+  String getById(
+    String id, [
+    List<dynamic> args = const [],
+  ]) {
+    return _currentMessages.generateStringAtId(id, args);
+  }
+
+  static Iterable<String> get knownLocales => _dataFiles.keys;
+
+  Future<void> loadLocale(String locale) async {
+    if (!_messages.containsKey(locale)) {
+      final info = _dataFiles[locale];
+      final dataFile = info?.$1;
+      if (dataFile == null) {
+        throw ArgumentError('Locale $locale is not in $knownLocales');
+      }
+      if (locale == 'de') {
+        await HomePage_de_empty.loadLibrary();
+      } else if (locale == 'en') {
+        await HomePage_en_empty.loadLibrary();
+      }
+
+      final data = await _assetLoader(dataFile);
+      final messageList = MessageListJson.fromString(data, _pluralSelector);
+      if (messageList.preamble.hash != info?.$2) {
+        throw ArgumentError('''
+              Messages file for locale $locale has different hash "${messageList.preamble.hash}" than generated code "${info?.$2}".''');
+      }
+      _messages[locale] = messageList;
+    }
+    _currentLocale = locale;
+  }
+
+  Future<void> loadAllLocales() async {
+    for (final locale in knownLocales) {
+      await loadLocale(locale);
+    }
+  }
+
+  String helloAndWelcome(
+    String firstName,
+    String lastName,
+  ) =>
+      _currentMessages.generateStringAtIndex(0, [firstName, lastName]);
+
+  String helloAndWelcome2(
+    String firstName,
+    String lastName,
+  ) =>
+      _currentMessages.generateStringAtIndex(1, [firstName, lastName]);
+
+  String newMessages(int newMessages) =>
+      _currentMessages.generateStringAtIndex(2, [newMessages]);
+
+  String newMessages2(
+    String gender,
+    int newVar,
+  ) =>
+      _currentMessages.generateStringAtIndex(3, [gender, newVar]);
+}
+
+Message _pluralSelector(
+  num howMany,
+  String locale, {
+  required Message other,
+  Message? few,
+  Message? many,
+  Map<int, Message>? numberCases,
+  Map<int, Message>? wordCases,
+}) {
+  return Intl.pluralLogic(
+    howMany,
+    few: few,
+    many: many,
+    zero: numberCases?[0] ?? wordCases?[0],
+    one: numberCases?[1] ?? wordCases?[1],
+    two: numberCases?[2] ?? wordCases?[2],
+    other: other,
+    locale: locale,
+  );
+}

pkgs/messages/example/pubspec.yaml

@@ -26,4 +26,4 @@ package_options:
     plural_selector: intl
     arb_input_folder: assets/l10n/
     message_output_folder: assets/
-    generated_code_file: lib/messages.g.dart
+    generated_code_files: lib/

pkgs/messages/examples_flutter/my_application/android/.gitignore

@@ -0,0 +1,13 @@
+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java
+
+# Remember to never publicly share your keystore.
+# See https://flutter.dev/to/reference-keystore
+key.properties
+**/*.keystore
+**/*.jks

pkgs/messages/examples_flutter/my_application/android/app/build.gradle

@@ -0,0 +1,48 @@
+plugins {
+    id "com.android.application"
+    id "kotlin-android"
+    // The Flutter Gradle Plugin must be applied after the Android and Kotlin Gradle plugins.
+    id "dev.flutter.flutter-gradle-plugin"
+}
+
+android {
+    namespace = "com.example.my_application"
+    compileSdk = 34
+    ndkVersion = flutter.ndkVersion
+
+    compileOptions {
+        sourceCompatibility = JavaVersion.VERSION_1_8
+        targetCompatibility = JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        jvmTarget = JavaVersion.VERSION_1_8
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId = "com.example.my_application"
+        // You can update the following values to match your application needs.
+        // For more information, see: https://flutter.dev/to/review-gradle-config.
+        minSdk = 33
+        targetSdk = 34
+        versionCode = flutter.versionCode
+        versionName = flutter.versionName
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig = signingConfigs.debug
+        }
+    }
+}
+
+flutter {
+    source = "../.."
+}
+
+dependencies {
+  implementation "com.google.android.play:core:1.10.3"
+}

pkgs/messages/examples_flutter/my_application/android/app/src/debug/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android">
+    <!-- The INTERNET permission is required for development. Specifically,
+         the Flutter tool needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>